Fan blade and shaft assembly mounting arrangement of a bathroom exhaust fan

ABSTRACT

A fan blade and shaft mounting arrangement for bathroom exhaust fan includes a housing, a fan blade which has a hub, a center tube at the center of the hub and blades arranged around the hub, a fan shaft inserted through the center tube of the fan blade and supported between two bearing members in the housing, and a torsion spring that has a torsionable portion sleeved onto the fan shaft and a positioning portion fastened to the fan blade. When the fan shaft is rotated, the torsionable portion of the torsion spring is twisted and secured firmly to the fan shaft so that the fan blade is rotated with the fan shaft.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to exhaust fans and more particularly to a fan blade and shaft assembly mounting arrangement of a bathroom exhaust fan.

2. Description of the Related Art

For air convection and ventilation, a bathroom is usually equipped with a bathroom exhaust fan. When using the bathroom, one turns on the bathroom exhaust fan to draw or guide air to flow.

A regular bathroom exhaust fan has a fan blade mounted on the inside. The shaft of the fan blade is mounted in a sleeve bearing. When the motor rotates the fan, a flow of air is produced. During rotation of the fan blade, the sleeve bearing supports the shaft and provides lubrication, stabilizing the rotation of the fan blade.

However, a bathroom exhaust fan is normally installed in the ceiling of a bathroom at the center area. The flow of air thus produced must flow directly from the bathroom to the outside open air. However, a bathroom exhaust fan of this kind has a low air volume output and a poor air drawing effect. Further, the use of sleeve bearings of the aforesaid bathroom exhaust fan design complicates its installation. When the fan blade rotates to produce a flow of air, dust and pollutants are carried with the produced flow of air, and some of them will be adhered to the sleeve bearing. When the sleeve bearing is covered with a certain amount of dust after a long use of the bathroom exhaust fan, the sleeve bearing will no longer lubricate the fan shaft, causing noises and unstable rotation of the fan blade. When this problem happens, the shaft and the sleeve bearing must be cleaned or replaced. Further, because a bathroom exhaust fan works under a high moisture environment, the sleeve bearing wears quickly with use. As a result, the service life of the bathroom exhaust fan is further reduced.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a fan blade and shaft mounting arrangement for bathroom exhaust fan, which is easy and convenient to install. It is another object of the present invention to provide a fan blade and shaft mounting arrangement for bathroom exhaust fan, which has a long service life and low level of noise. It is still another object of the present invention to provide a fan blade and shaft mounting arrangement for bathroom exhaust fan, which has a high wind pressure and high air volume output, providing an excellent airflow performance.

To achieve these and other objects of the present invention, a fan blade and shaft mounting arrangement for bathroom exhaust fan comprises a housing, and a fan blade and shaft assembly mounted in the housing. The fan blade and shaft assembly comprises a fan blade, which comprises a center tube and a plurality of blades arranged around the center tube, a fan shaft inserted through the center tube, and a locating member, which comprises a torsionable portion sleeved onto the fan shaft and a positioning portion fastened to the fan blade. When the fan shaft is rotated, the torsionable portion of the locating member is twisted and secured firmly to the fan shaft so that the fan blade is rotated with the fan shaft.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a bathroom exhaust fan constructed in accordance with the present invention.

FIG. 2 is a sectional view of the bathroom exhaust fan of FIG. 1 in an enlarged scale, showing the structure of the fan blade and shaft mounting arrangement.

FIG. 3 is an exploded view of the fan blade and shaft mounting arrangement in accordance with the present invention.

FIG. 4 is a perspective view of the fan blade and shaft mounting arrangement according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a bathroom exhaust fan comprises: a housing 20, and a fan blade and shaft assembly 10 mounted in the housing 20. The housing 20 has its bottom side covered with a bottom cover 24 that has a plurality of air inlet holes 22, and its top side provided with an exhaust port 26. The fan blade and shaft assembly 10 comprises a fan blade 30, a fan shaft 40, and a locating member 50.

Referring to FIGS. 2 and 3, the fan blade 30 comprises a hub 32, a center tube 34 formed integrally on the inner surface of the hub 32 at the center, a receptacle 36 formed integrally on the outer surface of the hub 32 at the center in communication with the inside space of the center tube 34, and a plurality of blades 38 formed integrally with the periphery of the hub 32. As shown in FIG. 4, each blade 38 has a sloping segment 60 and an extension segment 62. The extension segment 62 extends vertically upwardly from one side of the sloping segment 60. The sloping segments 60 of the blades 38 are partially overlapped with respect to one another around the hub 32, keeping the extension segments 62 in parallel.

The fan shaft 40 has a pointed endpiece 42 axially disposed at each of its two distal ends, and a winding 44 arranged around its periphery. The fan shaft 40 is inserted through the center tube 34 of the fan blade 30 so that the winding 44 is held to the fan shaft 40 corresponding to a magnetic device 46 in the housing 20 and the two pointed endpieces 42 are respectively stopped in a respective bearing member 28 in a respective socket 25 in the housing 20. When electric current is connected to the winding 44, the magnetic force of the magnetic device 46 causes the winding 44 to rotate, and therefore the fan shaft 40 is rotated with the winding 44 between the two bearing members 28. The bearing members 28 are made of ceramics or any other suitable friction-resistant material. Further, a spring member 29 is provided between one socket 25 and the associated bearing member 28, enhancing the coupling between the bearing members 28 and the fan shaft 40 and allowing adjustment of the coupling.

The locating member 50 is a torsion spring, having a torsionable portion 52 and a positioning portion 54. The torsionable portion 52 is sleeved onto the fan shaft 40 and accommodated in the receptacle 36 of the fan blade 30. The positioning portion 54 extends outwards from one end of the torsionable portion 52 and fastened to the hub 32 of the fan blade 30.

When the fan shaft 40 is driven to rotate, the torsionable portion 52 of the locating member 50 is turned with the fan shaft 40. Because the positioning portion 54 is fastened to the hub 32 of the fan blade 30, rotation of the fan shaft 40 causes the torsionable portion 52 to be twisted and then firmly secured to the fan shaft 40. Once the torsionable portion 52 is firmly secured to the fan shaft 40 during rotation of the fan shaft 40, the fan blade 30 is rotated with the fan shaft 40.

Further, because the sloping segments 60 of the blades 38 are partially overlapped with respect to one another around the hub 32, there is no gap in between each two adjacent blades 38 on the front side of the fan blade 30. During rotation of the fan blade 30, air flows along the surface of the sloping segments 60 of the blades 38 toward the respective extension segments 62 and then vertically upwardly away from the fan blade 30 along the extension segments 62, and therefore air flows from the air inlet holes 22 to the exhaust port 26 smoothly without any obstruction or turbulence. Therefore, the bathroom exhaust fan has a relatively higher air volume output and wind pressure with less noise of wind shear compared to prior art bathroom exhaust fans.

When installing the fan blade 30 and the fan shaft 40, fasten the fan blade 30 and the locating member 50 to the fan shaft 40, and then couple the fan shaft 40 between the bearing members 28 at the respective sockets 25 in the housing 20. Therefore, the installation of the fan blade and shaft assembly 10 is simple and rapid without using any screw or employing any secondary processing or insert injection.

Further, the fan shaft 40 is directly supported between the bearing members 28 in the respective sockets 25 in the housing 20, no sleeve bearing is used. Working for a long time or under a dusty or dirty environment, the coupling between the fan shaft 40 and the bearing members 28 remains normal and stable, and the fan shaft 40 will not be covered with dust or oil stain. Therefore, the blade and shaft assembly 10 has a long service life, and does not produce excessive noise even when it has worked continuously for a long time.

In conclusion, the invention provides a fan blade and shaft assembly 10 for bathroom exhaust fan, which is easy to install and has the advantages of long service life, low level of noise, high air volume output, high wind pressure and excellent performance.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. 

1. A fan blade and shaft mounting arrangement, comprising: a fan blade, said fan blade comprising a center tube and a plurality of blades arranged around said center tube; a fan shaft inserted through said center tube; and a locating member, said locating member comprising a torsionable portion sleeved onto said fan shaft and a positioning portion fastened to said fan blade; wherein when said fan shaft is rotated, said torsionable portion of said locating member is twisted and firmly secured to said fan shaft so that said fan blade is rotated with said fan shaft.
 2. The fan blade and shaft mounting arrangement as claimed in claim 1, wherein said blades of fan blade are overlapped with respect to one another.
 3. The fan blade and shaft mounting arrangement as claimed in claim 1, wherein said fan blade further comprises a hub and a receptacle formed integrally on the center of an outer surface of said hub in communication with the inside of said center tube; said center tube is formed integrally on the center of an inner surface of said hub in axial alignment with said receptacle; and said blades are formed integrally with the periphery of said hub.
 4. The fan blade and shaft mounting arrangement as claimed in claim 1, further comprising a housing and two bearing members mounted in said housing at different elevations to support said fan shaft therebetween.
 5. The fan blade and shaft mounting arrangement as claimed in claim 4, wherein said bearing members are made of ceramics.
 6. The fan blade and shaft mounting arrangement as claimed in claim 4, wherein said bearing members are made of a friction-resistant material.
 7. The fan blade and shaft mounting arrangement as claimed in claim 4, further comprising at least one spring means supported between said housing and at least one said bearing member to force said bearing members into connection with said fan shaft.
 8. The fan blade and shaft mounting arrangement as claimed in claim 4, wherein said housing comprises two sockets that accommodate said bearing members respectively.
 9. The fan blade and shaft mounting arrangement as claimed in claim 1, wherein said locating member is a torsion spring.
 10. The fan blade and shaft mounting arrangement as claimed in claim 1, wherein each said blade comprises a sloping segment and an extension segment extending vertically upwardly from one side of said sloping segment, the sloping segments of said blades being partially overlapped with respect to one another around said hub to keep the extension segments of said blades in parallel. 